Transformer for radiocircuits



Jan. 17,1928.

. 1,656,209 5. D. LIVINGSTON TRANSFORMER FOR RADI OCIRCUITS Original Filed Sept. 12, 1923 INVENTOR fironley 0. llwhqsfon ATI'OR Y PatentedJen. 17, I928.

UNITED STATES 1,656,209 PATENT, OFFICE.

STANLEY D. LIVINGSTON, OF FBEEPOBT, NEW YORK, ASSIGNOB TO EISEMANN MAG- NETO CORPORATION, OF BROOKLYN, NEW YORK, A CORPORATION OF NEW YORK.

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Original application filed September 12, 19%, Serial No. 662,177. Divided and this application filed July 8, 1925. Serial No. 8,124.

My invention is for an improved construction of radio-frequency transformer embodying various features of novelty of prior devices, as will appear from a detailed description of the accompanying drawings which form part of this specification. In these drawings,

Fig. 1 represents a side view of a transformer constructed in accordance with my invention, one half of the device being shown in longitudinal cross-sections;

Fig. 2 shows the transformer mounted in a socket having terminals properly connected in circuit;

Fig. 3 is an end view of the transformer;

Fig. 4 is a bottom view showing the contacts projecting from the plug of the transformer;

Fig. 5 is an inside view of one of the at: half shells which constitute the outercasing of the transformer; and

Fig. 6 is an enlarged fragmentary view in cross-sections to show how the concave transformer contacts are in looking engagement with the rounded contact heads of the transformer socket.

The parts of the transformer are mounted in an outer shell or casing indicated as a whole by C. This casing is preferably molded out of composition material suitable for that purpose, such as bakelite or the like. In the preferred form of my invention, the outer shell C comprises two identical half sections 1 and 2. Each shell section is formed with a cylindrical recess '3 and a semi-cylindrical projection 4. Each projection 4 is formed with a recess 5 and a passageway 6 leading into the recess or chamber 3. When the two halves or sections 1 and 2 are assembled, they constitute a closed outer shell. The semi-cylindrical projections 4 fit together to form a cylindrical plug, which I will designate as a whole by G. The plug G is constructed to 4 fit into a socket F mounted on a base plate B, which ma form part of a radio-frequency ampli er unit. The socket F comprises an outer shell 7 and tour insulated spring contacts 8, three of which are shown in Fig. 2. The arrangementlot these contacts is similar to that of the well-known vacuum tube socket contacts, and will therefore be understood without further description. The transformer socket is very similar to the standard lam socket, except that the shell 7 is considera ly lower than the usual -vacuum tube socket shell. This difference in the heights of the two shells, makes it impossible to insert a vacuum tube by mistake into socket F, or to insert the transformer into a vacuum tube socket. A pair of'pms 9, projecting laterally from the plug G at diametrically opposite points,

are adapted to engage correspondingly arranged bayonet slots 10 in the shell 7 of the transformer socket F to insure correct positioning of the plug in the socket. Only one of the slots 10 is shown in Fig. 2, but the location of the other slot will be clearly understood. The shell sections 1 and 2 are provided with holes 11 through which pass bolts 12 for rigidly securing the two halves together. It will be seen from Figs. 1 and 4 that when'the two shell sections are bolted together, they are in contact along a plane indicated by the line T, this plane being substantially at right angles to the longitudinal axis L of the cylindrical chamber or compartment formed by the recesses 3 of the two shell sections.

Within the cylindrical chamber 3 of the shell G are mounted the two transformer windings K and K. Either winding may be the primary, depending upon the positionof the plug G in socket F, as will presently be explained. These windings are in the form of cylindrical coils, which fit snugly in the chamber 3, as best shown in .Fig. 1. In the chamber 3 is supported a magnetic core M of suitable construction. Personally, I prefer a core consisting of alternate layers of paper and thin sheets of magnetic material. .The core M is hollow and the ends thereof engage projections 13 extending inwardly from the ends of the shell sections 1 and 2. In this way the magnetic core M is supported centrally with respect to the windings K and K and is spaced therefrom by an air gap 14.

This arrangement of core and windings has certain practical advantages. The windings Kand K are separated sufficiently to reduce the distributed capacity to the lowest practical value. While this separation of the windings also reduces their mutual inductance, the magnetic core M increases the inductance to the required value. Now, the introduction of an ordinary magnetic core in a radio-frequency transformer would again raise the distributed capacity above may be present introduces merely neg tial. For instance, in tuned radio frequency,

where one winding is tuned with a condenser, the magnetic core may be omitted.

In the plug G of the transformer are embedded four contacts 15, 16, 17 and 18. Contacts 15 and 16 are embedded in one plug section, and contacts 17 and 19 in the other plug section. These contacts project into the shallow recess 5 formed in each shell section, as ma be seen from Fig. 5, so that the ends of each winding may be connected to the pair of contacts carried by the sameshell half or section. For instance, the ends of winding K are connected to contacts 15 and 16, and the ends of widing K- are connected to contacts 17 and 18. The ends of the windings are led .to their respective contacts through the passa e 6. By virtue of this construction, each alf of the outer casing contains one winding connected to a pair of outer terminals. Each half is thus complete with its winding, contacts and connections, so that no cross-connections are necessary when the two halves are'fastened -together. This makes it easy to insert the coils 1n place and connect than with their respective contacts or terminals in the plug. gas til: tiansfoi'mer is inserted in tile et e ourpugcontactsengaget e socket contacts 8, which are supposed to be properly connected in circuit. These connections are well understood and need not be shown. The windings K and K may have a one-to-one ratio, in which case it is immaterial which winding is the primary and which I the secondary when the transformer is in,

serted in the socket. In certain cases, how-- ever, I prefer to make the windiugs'of an unequal number of turns. For example,'th e ratio'of turns in windings K and'K' may be about 2:1, the long winding K being the .primary and'the short winding K the secondary. If the plug G is so in socket F that the position of the windingsK and K is the reverse of that indicated in Fig. 2, the short winding K becoms the primary, and thelong K is then the secondary. To cite an instance by wayof illustration, I found in practice that with a -2:1ratiointhewindings,thetuningrange for short waves eame well within 150-400 275-750 meters. Other will give difand for longer waves hetnlveentransformer plug so. inserted 'that the vdotted lines :0 the long coil K is connected...

' able locking means consists in f0 In order to inform the operator which po- 'sition of the transformer in socket F produces' a step-up or step-down relation of the windings, a suitable mark or indicator is provided. In 2, the outer shell C has a mark a: so arranged that, when this markis toward the front of .the base, the short coil K functions as secondary; when the mark is in the position indicated by the in circuit as the secondary and is 'tuned by the condenser. It will be understood that I any other practical indicating means may be employed.

In order to prevent accidental in socket F, I provide means for releasably locking the plug contacts to the socket contacts. In the present this releassocket contact 8 with a rounded heat 19, as

indicated in the enlarged view of Fig. 6. Each plug contact terminates in a hollow or concave projection 20, which snaps over the rounded head 19 when the pl position in the socket. It will understood that the contacts of the transformer socket F, like those of a lamp socket, are resiliently supported. Therefore, the rounded heads 19 of the socket contacts snap into the ML.

low ends 20 of the transformer'plug'contacts, when the transformer is in proper position in the socket, as predetermined by the 9 engaging in the bayonet slots 10 I of ell 7. The horizontalportions of the 1 bayonet slots 10 lock the transformer plug axial movement outof the socket. T e locking en ent between the rounded heads 19 of the socket contacts and the hollow ends 20 of the transformer plug ter- 1 -as above-described, while locking these parts together ration permits rotation ofthe transformer plug f remo'val from the socket.

emhodiedin other forms than herein set no without departing from the scope of my' invention as defined theappended This application is filed asa. division of my copending case Serial Number 662,177 12, 1923, in which an oilicial requirement was made for the cancellation of all claims on the transformer construca rotation of the transformer plug after being inserted each is in proper 1' against accidental sepa- Although I have herein shown and de- 1175- 'What I claim as my invention isi 1. A radio transformer comprising an outer shell consisting of two complementary sections adapted wheii assembled to form a chamber and a plug, a primar windin in the chamber of one section an a secon ary winding in the chamber of the other section,

along a plane passing transversely through said hollow part and said plug, a winding in the hollow portion of each half shell, a pair of contacts mounted in and projecting m'the plug section of each half shell, the

ends of each winding being connected to the associated contacts, and means for securing the half shells together.

3. A radio transformer comprising anouter .shell consisting of a substantially cylindrical hollow part and aplug projecting from said hollow part substantially at right angles .to the axls of said art, said shell bein divided-into two simi ar halves alon a p ane passing transversely through said ollow part and said plug, a winding 1n by said core is supported. lengthwise in said hollow part independently of said windings,

the hollow portion of each half-shell, a pair of contacts mounted in and rojecting from the plug section of each hal shell, the ends of each winding being connected to the associated contacts, a magnetic core passin axiall through said windings and spac there rom, the ends of said core engaging the opposite ends of said hollow part, whereand means for securing the half shells to.- gether. I

4. A radio transformer comprising an outer shell consisting of a substantially air of contacts mounted-in and cylindrical hollow part and a plug projecting'from saidhollow, part substantially at right angles to the.ax1s of said art, said shell bein divided into two simi ar'halves alon a p ane passin transverselythrough said ollow part an said plu a winding in the hollow portion of each alf shell, a projecting m the plug section of each hal shell, the ends of each winding being connected to the associated contacts, a hollow magnetic core passing axiallyflthrough said windings and:

spaced therefrom, insiderojections at the opposite ends of said ho ow part for removably engaging the endsof said core, whereb sai core is supported lengthwise in said ho pw pag g and removable therefrom of substantially T- sha without disturb? said windings, meam U for securing the alf shells together.

5. In a radio transformer a cylindrical shell consisting of two h ves separable along a transverse plane, a winding in' each half shell, and a ma etic core supported 70 axially in said shell independently of said. windings, said core passing through said windings-and being's' aced therefrom. 6. In a radio tran ormer a cylindrical shell consisting of two ha ves separable 75 along a transverse plane, inside promotions at the opposite ends of said shell, a winding ea'chhalf shell, and a magnetic core extending axially through said windings and being spaced therefrom, the ends of said 00 core being in supporting engagement with said pro ections.

7. As a new article of manufacture for use in radio transformers, an outer shell consist' of two substantiall identical half sections adapted to fit toget er to form a closed -c lindrical, chamber and a plug, each plug alf'being rovided with a recess communicating with t e chamber of the section, and contacts embedded in each plug .0

half and extending from said to the piutdside of the plug, for the purposes specie 8. As a new article .offmanufacture for use in radio transformers, an outer shell of molded material consisting of two substantially identical half sections each section comprising a hollow' cylindrical portion with a semi-cylindrical portion projectin therefrom at rlght angles to the axis of sai l hollow portion, said sections being adapted v to fit together to form a closed cylindrical chamber and a cylindrical lug exten transiggasely therefrom, .for the pu rposaa 9. In a radio transformer, an outer shell form, one part of said shell containingt e wind and the other part constituting-a plug adapted to fit in a socket, said tfiling having contacts conno nected to the win 10. A radio-frequency transformer having a prir of spaced windings a 'in axial a 'gnmen't, 'a cylindrica magnetic core passing axially through said windings and DI uniformly spaced from each winding by an annular air p, andmeans engaging only the ends 0 said core for supporting the same in position. p

11. A radi -frequency transformer having a pairof spaced windings,a' magnetic core passing axially through saidwin and spaced from each winding by an'a'irgap', said core being cylindrical and oompr sing thin sheetsof magnetic material I. separated by insulating sheets, and means for supportm saidc'ore in-that 'tion.

:ST YD.LIVIN STON. 

